Adding-machine.



R. L. BURD.

ADDING MACHINE.

APPLICATION FILED AUG.8.1913.

1,221,829. Patented Apr. 10, 1917.

. v 2 SHEETS-SHEET l.

R. L. BURD.

ADDING MACHINE.

APPLICATION HLED AUG.8, 913. 1,221. ,829. Patented Apri 191? I 2 SHEETSSHEET 2.

UNITED STATES PATENT oFFIoE;

ROY I1. BURD, OF CHICAGO, ILLINGIS, ASSIG-NOR TU BURROUGHS ADDINGMACHINE COMPANY, OF DETROIT, MICHIGAN,

A CORPORATION OF MICHIGAN.

ADDING-MACHINE.

To all whom e't may concern Be it known that I, ROY L. Born), a citizenof the United States residing at Chicago, in the county of Look andState of Illinois, have invented certain new and useful Improvements inAdding-Machines, of which the following is a specification.

' This invention relates to the type of adding machines shown in priorPatents Nos. 1,016,501, and 1,023,168 issued February 6, 1912, and April16, 1912, respectively. In these machines the turning of wheels toeffect registration is done by return of spring-actuated levers afterdisplacement thereof by depressible keys and release of the latter. Thekeys are arranged in rows each row made up of nine keys numbered from 1to 9 and constructed and arranged to act upon the associated registeringlever at varying distances from its pivot, the 9- key' acting nearestthe pivot, the S-key' a step farther away and soon. Upon reference tosaid prior patents it will be observed that the acting lugs of the keysare not normally in engagement with the lever, the latter being stoppedin its return movement by contact of its forward end with a than thelugs of other keys.

cross bar, and will further be observed that the lugs of the lowerdenomination keys 1 and 2 are spaced farther from the lever This is sobecause of a purpose to arrange for uniform dip or extent of depressionof all of the keys while at he same time preserving a compactarrangementof the keys with their.

tops spaced. slightly and uniformly from each other from front to rear.The keys are normally upheld by comparatively light springs and beenfound that, owing to the relatively slight resistance to depressionofthe lower denomination keys prior to their striking the lever, there maybe a failure to fully depress these keys against the considerablygreater resistance offered by the relatively strong spring which upholdsthe lever, The lost motion between the lugs of the other keys and thelever is so slight that the variation in resistance to their depressiondoes not have to be taken into account, the extent of their depressionSpecification of Letters Patent.

- end against a frame cross rod a Patented Apr. 10, 1917. Serial No.783,701.

of depression against the lighter resistance 18 of such extent as to bedistinctly notice able so that there is an inclination to relax thepressure when the heavier resistance is encountered.

The purpose of the present invention is to compensate for this greaterextent of movement of the lower denoinination'keys against the lightresistance so that there will be no noticeable increase in resistancesuch 'as to lncline the operator to relax the finger pres sure. It willof course be understood that failure to fully depress the key leads 'toerroneous registration. i

In the particular form of embodiment of my invention here illustrated, Iinterpose resistance to the depression of the lower denomination keyswhich, added to the re sistance offered by the light springs normallyupholding the keys, substantially equals the resistance of the leverspring.

.111 the drawings which accompany and form part of this specification,Figure 1' represents in sectional right-side elevation a machine of thetype shown in the aforesaid prior patents, having embodied therein meansfor carrying out the present invention; Fig, 2 is a similar view showingthe lowest denomination key depressed; Fig. 3 a perspective view of oneof the special parts employed to carry out my invention.

The machine proper requires no detailed description on account of itsbeing fully explained in said patents. It will therefore suflice todesignate only such elements of said machine as are immediatelyassociated with the new parts introduced for carrying out thepresent'invention. D designates the stems of a row of keys and F theregistering lever upon which these keys act through the medium of lugs dstruck out from said stems and extending over the upper edge of thelever. 'Said lever is normall" uphe d by a relatively strong spring F-w1th its front as shown in Fig. l. The relatively slight spacing fromthe lever of the lugs d of seven of the ke stems-counting from the rightof Fig, lwi be noted and the greater spacing from said lever of the lugs03 of the other two keys which are ones bearing the numerals 1 and 9;;

For the purpose of carrying out my present invention, I pivot upon thelever F another lever or arm l0and form the latter with two raisedportions or stepped shoulr be immediately resisted -slight additionalresistance offered by ders 10" and 10 for engagement with the lugs ofsaid 1 and 2-keys respectively as illustrated in Fig. l. Said lever orarm 10 is pivoted at its rear end to the lever F as shownat 10 and at aforward point has a depending finger 10 whose lower extremity isconnected by a spring 11 with a forward portion of the lever F, saidspring obviously tending to lift the arm or lever 10. This action islimited by the encounter against the under edge of the lever F of thelug l0 struck out from a .portion of the lever or arm 10.adjacent thefingerlO 'Normally the shoulders 10 and 10 are close up under the lugsof the 1 and 2-keys respectively as shown in Fig. 1, the steppedrelation of said two shoulders being accommodated to the slightlygreater spacing of the lug of the l-key above the lever F as comparedwith the spacing of the lug of the 2-key above said lever.

The keys are normally upheld as usual by light spring 0! surrounding thenarrowed lower portions of their offered by these springs to depressionof the keys being very slight as compared with the resistance offered bythe spring F which uphplds the registering lever; However, as to the 1and Q-keys it will be obvious that, with the new parts abov e describedincorporated in the machine, their depression will by the spring 11 Thecharacter and disposition of this spring 11 is such however andthe'relation of the lever 10 to the lever F of such character that saidlever will move downwardly upon its pivot, the spring yielding, withoutany accompanying movement of the lever F. Obviously, therefore,depression of the l or Z-keys the distances necessary to bring its lug(Z into engagement with the upper edge of the lever F,-what may betermed the lost motion of the key, is resisted by the spring 11. Thisadds appreciably to the resistance offered by the light key-spring d sothat the sum total of the'resistance approximates that encountered bythe key when it strikes the lever F. Consequently there is no suchsudden encounter of the key with the relatively heavy resistance of theregistering lever as heretofore experienced and therefore no inclinationon the part of the operator to relax finger pressure and so fail tocompletely depress the key. Of course when the lug of the key strikesthe lever F there is no further movement of the arm or lever 10 aboutits pivot and no further stretching of the spring 11 so thatthe furtherdepression of the key is against the resistance offered by the spring Fand tlfie t e spring d, the same as in the prior structures.

While it will be seen that the above-described structure accomplishesthe desired result in an exceedingly simple and efiicient stems, theresistance manner I wish it understood that my invention is not limitedto embodiment in this particular form but may be embodied in a varietyof forms.

I claim: 1. In a machine of the class described the combination of areglstering lever; a serles 0 keys with stems constructed and arrangedto act upon said lever atincreasing distances from the latters pivot andwith lost motion between the lever and certain of said key stems whichact at the greater distances; and compensating means for motion; betweensaid certain key stems and the lever is being taken up, whereby tocreate substantiallyuniform resistance to the depression of said certainkey stems though displacement of the lever by them is lessproportionately to the extent of their depression than is displacementof said lever by other key stems proportionate to similar extent ofdepression of thelatter, such other key stems'acting independently ofsaid compensating means.

2. In a machine of the class described the combination of a registeringlever; a series of keys with stems constructed and arranged to act uponsaid lever at increasing distances from the latters pivot and with lostmotion between the lever and certain of said key stems which act at thegreater distances; and compensating means for the said certain key stemsonly, said means ofierin resistance thereto while said lost motionetween the said certain key stems and the lever is being taken up,whereby to create substantially uniform resistance of said certain keystems though displacement of the lever by them is less proportionatelyto the extent of their depression than is displacement of said lever byother key stems proportionate to similar extent of depression of thelatter, such other key stems acting independently of said compensatingmeans. .i

3. In a machine of the class described, the combination of a spring-heldregistering lever, a series of depressible spring-upheld keys with stemsconstructed and arranged to act upon said lever in opposition to itsspring at increasing distances from its pivot and with lost motionbetween the levers and certain of said key stems which act at thegreater distances, and compensating springmeans applied to such keystems only and offering resistance to their depression while the lostmotion between them and the lever is being taken up, whereby to createsubstantially uniform resistance tothe depression of said certain keystems though displacement of the lever by them is less proportionatelyto the extent of their depression than is displacement of said lever byother key stems proportionate to similar the said certain key stemsonly, said means acting while said lost to the depression extent ofdepression of the latter, such other key stems acting independently ofsaid compensating means.

e. In a machine of the class described, the combination of a spring-heldregistering le- Ver, a series of depressible spring-upheld keys withstems constructed and arranged to act upon said lever in opposition toits spring at increasing distances from its pivot 10 and With lostmotion between the lever and certain of said key stems which act at thegreater distances, an arm pivoted on said lever, and a spring upholdingsaid arm for Witnesses:

FRANK PARKER DAVIS, ROBERT DOBBERMAN.

